Submission #1226251

#	Time	Username	Problem	Language	Result	Execution time	Memory
1226251		abdelhakim	Sorting (IOI15_sorting)	C++20	0 / 100	1 ms	580 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
#define dbg(x) cerr << #x << ' ' <<x << endl;
#define ll long long
using namespace std;
vector<ll> ind;
vector<ll> dest;
vector<ll> recip;
vector<ll> s;
void swp(ll i, ll j)
{
	swap(s[i],s[j]);
	swap(ind[s[i]],ind[s[j]]);
	swap(dest[s[i]],dest[s[j]]);
	recip[dest[s[i]]]=s[i];
	recip[dest[s[j]]]=s[j];
}
bool is_sorted()
{
	for (int i=0;i<s.size();i++)
	{
		if(s[i]!=i)return false;
	}
	return true;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    P[0] = 0;
	Q[0] = 0;
	ind.resize(N);
	dest.resize(N);
	recip.resize(N);
	for (int i=0;i<N;i++)
	{
		s.push_back(S[i]);
	}
	for (int i=0;i<N;i++)
	{
	  ind[s[i]]=i;
	}
	for (int i=0;i<M;i++)
	{
		P[i]=0;
		Q[i]=0;
	}
	if(is_sorted())
	{
		return 0;
	}
	ll l=1;
	ll r=M;
	ll ans=M;
	while(l<=r)
	{
		ll mid=(l+r)>>1;
		for (int i=0;i<N;i++)
		{
			s[i]=S[i];
			ind[s[i]]=i;
		}
		for (int i=0;i<M;i++)
		{
			P[i]=0;
			Q[i]=0;
		}
		vector<ll> l3iba(N);
		for (int i=0;i<N;i++) l3iba[i]=s[i];
		for (int i=0;i<mid;i++)
		{
			swap(l3iba[X[i]],l3iba[Y[i]]);
		}
		for (int i=0;i<N;i++)
		{
			dest[l3iba[i]]=i;
			recip[dest[l3iba[i]]]=l3iba[i];
		}

		ll cur=0;
		for (int i=0;i<mid;i++)
		{
			swap(s[X[i]],s[Y[i]]);
			swap(ind[s[X[i]]],ind[s[Y[i]]]);
			for (;cur<N;cur++)
			{
				if(dest[s[cur]]!=s[cur])
				{
					P[i]=ind[s[cur]];
					Q[i]=ind[recip[s[cur]]];
					swp(P[i],Q[i]);
					break;
				}
			}
		}
		if(cur==N)
		{
			ans=mid;
			r=mid-1;
		}
		else
		{
			l=mid+1;
		}
	}
	// cout << "here" << endl;
	// for (int i=0;i<M;i++)
	// {
	// 	cout << X[i] << ' ' << Y[i];

	// }
	return ans;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 12
• Subtask 3: 0 / 16
• Subtask 4: 0 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26